For decades, HVAC heat exchangers have been comprised primarily of copper. However, in recent years due to the increase in the cost of copper, HVAC manufacturers have begun seeking more cost effective solutions for the materials from which they manufacture heat exchangers. One such alternative material is aluminum, but since aluminum is not as strong a material as copper, manufacturers have had to compensate for this material difference by increasing the thickness of the aluminum tubing, which in turn, decreases internal volume.